1. Field of the Invention
The present invention relates to highway safety systems. More particularly, the present invention relates to systems which provide variable speed limits.
2. Description of the Related Art
Conventional highways post speed limits by the use of painted metal signs. In general, a typical speed limit for an Interstate Highway is between 55 to 65 miles per hour. The posted speed limits assume ideal conditions and common sense on the part of motorists to slow down as the conditions change. However, inexperienced drivers, and impatient drivers can be seen on all major roadways trying to maintain the posted speed limit even when it would be dangerous to do so, such as during ice storms, snow storms, fog, hurricanes, sleet, etc.
Periodically, the news will report chain reaction highway crashes where dozens of cars and trucks were involved. The primary reason for these accidents is the drivers were not aware of the need to slow down according to changing conditions, or used poor judgment and attempted to drive at or above posted speed limits during bad weather. Sometimes, the results are catastrophic for the drivers, passengers and other motorists.
Some highway systems, such as the New Jersey Turnpike, use electronic speed limit signs at select areas of the highway. During bad weather, a person or persons at a central site of the Turnpike Authority decides to post a lower speed limit within established guidelines. However, this manual intervention is slow, and for instance, if the case of changing weather conditions, such as an unexpected hail storm, can not respond quickly enough or take into account varying conditions on different portions of the highway.
One aspect of the present invention is a system for providing the automatic setting of a variable speed limit, wherein a plurality of variable speed limit indicators arranged at predetermined intervals along a road will display different speeds according to weather conditions sensed by local sensors.
Such a system of the present invention may comprise:
a plurality of variable speed limit indicators arranged at predetermined intervals;
weather sensing means for sensing weather conditions of a road along a plurality of predetermined locations; and
regulating means for regulating a particular speed limit along each respective location of said plurality of predetermined locations, said regulating means communicating with said weather sensing means to correlate an output of said weather sensing means at said each respective location with a database comprising a matrix of speed limits according to the output of said weather sensing means for said each respective location;
wherein said regulating means automatically transmits a respective speed limit for display by a respective speed limit indicator of said plurality of variable speed limit indicators based on one of periodic and continuous communication of weather conditions from said weather sensing means.
The weather conditions are used to regulate the speed limit for each respective location by correlating with a database of predetermined speeds for each portion of the road according to the conditions sense. Historical accident information for each respective location may be used to adjust the speed limit to a safer level for more dangerous portions of a road.
In another aspect of the invention, a method for providing the automatic setting of a variable speed limit includes correlating received weather conditions with predetermined speed limits according to each possible weather condition for each respective location of the road.